As Facebook's 1.6 billion users - who hit the "Like" button 6 billion times a day - adjust to the change, advertisers will likely be assessing how to best convert the new flood of user data into sales and revenue.

At present, the value generated just by the "Like" button for Facebook is "priceless", Brian Blau, an analyst at Gartner, told Bloomberg. By collecting more granular data about users' sentiments, Facebook will be able to better target its ads and also improve the News Feed algorithm in order to surface more relevant posts.

Associate Professor David Glance, director of Centre for Software Practice at the University of Western Australia said the "Like" button had been problematic for advertisers because it didn't cover the subtleties.

"The degree of reaction is now captured and that's an important feature. It enables advertisers to be incredibly sophisticated about how they post their ads, refining them constantly," he said.

"The buttons, combined with your profile, demographic, your read habits and other information all now goes into the mix."

Mark Cameron, chief executive of strategic digital consultancy Working Three, said Facebook's business model was underpinned by ultra-targeted advertising and its goal was to create "complex psychometric profiles of users".

"Knowing all the brands, pages, people and posts someone "Likes" gives Facebook an amazing view of each of its users – adding an additional level of behavioural interactivity allows this to get even more sophisticated," he said in a column for BRW.

"It is very easy to imagine a world where someone, after seeing the post about a friend's parent passing away, hits a button that expresses "I'm sorry" and is then is presented with an ad for flowers delivery."

Facebook made a profit of $US3.7 billion ($5.2 billion) in 2015, up 25 per cent from a year earlier, its latest quarterly earnings report shows. Revenue grew by 43 per cent to $US17.9 billion.